Method for preparing D-psicose crystal

1. A method for producing D-psicose crystals having a grain size of MA200 μm or larger, comprising:

removing impurities from a D-psicose solution to obtain a purified D-psicose solution;

concentrating the purified D-psicose solution to provide a concentrated D-psicose solution having a concentration of 80 Brix (%) to 85 Brix (%);

performing rapid cooling of the concentrated D-psicose solution to 30° C. to 40° C. in a heat exchanger to provide a copied D-psicose solution having a temperature between 3° C. and 4° C., wherein the rapid cooling is performed at a cooling rate of 5° C. to 20° C. per hour;

placing the cooled D-psicose solution at a temperature between 30° C. and 40° C. to a crystallizer and adding D-psicose seed crystals to the crystallizer;

performing seeded crystallization of D-psicose in the crystallizer while controlling temperature to stay between 30° C. and 40° C., which provides a D-psicose massecuite having a temperature between 30° C. and 40° C.; and

performing full-scale crystallization of D-psicose using the D-psicose massecuite while controlling temperature to stay between 30° C. and 40° C., which provides D-psicose crystals having a grain size of MA200 μm or larger.

2. The method according to claim 1 , wherein the step of removing impurities from a D-psicose solution to obtain a purified D-psicose solution comprises:

decoloring the D-psicose solution by passing through a column packed with a decoloring agent;

desalting the decolored D-psicose solution via ion exchange resin chromatography; and

passing the desalted D-psicose solution through a continuous chromatography column packed with an ion exchange resin to which calcium activating groups are attached.

3. The method according to claim 2 , wherein the ion exchange resin used in the ion exchange resin chromatography is a 100% weak basic anion resin.

4. The method according to claim 2 , wherein the step of passing through a continuous chromatography column is a simulated moving bed (SMB) process.

5. The method according to claim 2 , wherein the D-psicose solution purified through the continuous chromatography column has a purity of 95% (w/w) or more.

6. The method for producing high purity D-psicose crystals according to claim 1 , wherein performing seeded crystallization comprises

adding seeds of D-psicose to the cooled D-psicose solution at a temperature between 30° C. and 40° C.; and

adding additional D-psicose solutions to the seeds-added D-psicose solution.

7. The method according to claim 6 , wherein the concentration of the additional D-psicose solutions is in a range of 80 Brix (%) to 85 Brix (%).

8. The method according to claim 6 , wherein the volume of the additional D-psicose solutions is in a range of 5 (v/v) % to 20 (v/v) % based on the volume of the seed-added D-psicose solution.

9. The method according to claim 1 , wherein the full-scale crystallization comprises:

adding another D-psicose solution having a purity of 95% (w/w) or higher and a concentration of 80 Brix (%) to 85 Brix (%) to the seed crystallized massecuite, and

subsequently, repeating heating and cooling the resulting solution within the range of 30° C. to 40° C.

10. The method according to claim 9 , wherein repeating heating and cooling the resulting solution comprises adding, to the resulting solution, an additional D-psicose solution at a temperature of 30° C. to 40° C. two times or more an interval of 10 hours to 20 hours.

11. The method according to claim 10 , wherein the additional D-psicose solution is added each time in an amount of 5 (v/v) % to 20 (v/v) % based on the volume of the resulting solution to which the additional D-psicose solution is added.

12. A method of crystallizing D-psicose, the method comprising:

concentrating a D-psicose solution to provide a concentrated D-psicose solution having a concentration of 80 Brix (%) to 85 Brix (%);

performing rapid cooling of the concentrated D-psicose solution to 30° C. to 40° C. to provide a cooled D-psicose solution having a temperature between 30° C. and 40° C., wherein the rapid cooling is performed by heat exchange at a cooling rate of 5° C. to 20° C. per hour;

placing, in a first crystallizer, the cooled D-psicose solution having a temperature between 30° C. and 40° C. and adding D-psicose crystal seeds to the first crystallizer;

performing seeded crystallization of D-psicose in the first crystallizer while controlling a temperature of the D-psicose solution in the first crystallizer to stay between 30° C. and 40° C., which provides a D-psicose massecuite;

placing the D-psicose massecuite to a second crystallizer and adding thereto a processed D-psicose solution to provide a crystallization mixture in the second crystallizer, wherein the processed D-psicose has a concentration between 80 Brix (%) and 85 Brix (%) and a temperature between 30° C. and 40°; and

performing crystallization of D-psicose in the second crystallizer while controlling a temperature of the crystallization mixture in the crystallizer to stay between 30° C. and 40° C., which provides D-psicose crystals having a grain size of MA200 μm or larger.

13. The method of claim 12 , wherein performing seeded crystallization in the first crystallizer comprises adding an additional D-psicose solution to the first crystallizer at least once, wherein the additional D-psicose solution is at a temperature between 30° C. and 40° C. when added.

14. The method of claim 12 , wherein performing crystallization in the second crystallizer comprises adding an additional D-psicose solution to the second crystallizer at least once, wherein the additional D-psicose solution is at a temperature between 30° C. and 40° C. when added.